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Fault code index · Victron VE.Bus, MPPT & VRM

Victron Fault Code Index

Every Victron alarm from the official VE.Bus, MPPT and VRM Portal documentation — what the code means, the most likely cause, and what to do next. Find your code below or browse by system area. Covers MultiPlus, Quattro, SmartSolar, BlueSolar and Cerbo GX.
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Book Victron diagnosisAll fault codes
  • Sourced from official Victron documentation — VE.Bus & MPPT error codes and the VRM Portal alarms manual
  • Linked to full Victron diagnostic guides where available
  • Covers MultiPlus, Quattro, SmartSolar, BlueSolar and Cerbo GX
Victron fault code you can't resolve?

If your Victron system is showing a VE.Bus or MPPT error, or VRM has sent an alarm and you're unsure what to do next (other than the whole installation going offline, which our VRM offline guide covers), a remote diagnostic identifies the root cause from your VRM data — typically within 30 minutes.

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Written by · Independent Solar Engineer Last updated

How to find your fault code. VE.Bus errors (MultiPlus, Quattro) show on the front-panel LEDs and, with a number, on a connected GX device and in VRM. MPPT "Err" codes (SmartSolar, BlueSolar) appear in the VictronConnect app over Bluetooth, on the controller display, or on a GX device. System alarms (Low battery, Overload, Temperature, High voltage, Communication lost) are named — not numbered — and are pushed from the GX device to VRM. Open VRM and check the alarm log for a timestamped history.

VE.Bus inverter/charger errors (Multi & Quattro)

VE.Bus errors come from MultiPlus, MultiPlus-II and Quattro inverter/chargers. They appear on the front-panel LEDs and, in plain text with a number, on a connected GX device (Cerbo GX, Color Control) and in VRM. Most are shown as "VE.Bus Error" with a number. Several auto-recover the moment the underlying issue clears; others keep the system off until it is restarted. Cabling between units must be machine-made patch leads — never self-crimped cables.

VE.Bus Error 1Device switched off because another phase switched off
In a multi-phase (split-phase or 3-phase) system, one phase shut down and took the others off with it. Error 1 is the knock-on effect, not the root cause — the real fault is a Low battery, Overload or High temperature alarm on one of the other units. Look at the GX device or VRM to see which phase actually raised the Low battery, Overload or Temperature alarm — that is the one to investigate. The system recovers on its own once the underlying alarm clears. If you can't tell which unit is at fault, book a free remote diagnostic and we'll read the VRM logs; FREE to diagnose, £125 only if we fix it.
VE.Bus Error 3Not all (or more than) the expected devices were found
The system can't see the right number of units on the VE.Bus network. Often appears together with Error 1 — fix Error 1 first. Common causes are a blown DC fuse in one unit (everything looks fine on mains, but the unit drops out the moment mains fails), faulty or self-crimped communication cables, or two separate systems wired together by mistake. This usually needs an engineer — DC fuses and the VE.Bus wiring sit inside the units. Note whether it only appears during a power cut (a classic blown-DC-fuse symptom). Do not open the inverter/charger. VE.Bus error guide →
VE.Bus Error 5Overvoltage on AC out
Victron defines Error 5 as overvoltage on the AC output. The documented cause is the AC wiring of one of the slave units not being connected properly, or not being connected at all, and the documented solution is to check that AC wiring. The system restarts automatically once the error is gone. This is mains-side wiring and is not a homeowner job. Get the installer or a qualified engineer to check the AC connections at every unit in the system, and do not open the inverter/charger. VE.Bus error guide →
VE.Bus Error 8 / Error 11 Ground relay test failed / Relay test fault
The inverter/charger ran its automatic safety self-test on the internal earth and back-feed relays and it failed, so the unit will not connect to the grid. On MultiPlus-II and EasySolar-II this is most often an installation or wiring problem rather than a broken unit, but it is a protective shutdown and must not be ignored. Causes include neutral-to-earth wiring not done correctly for your installation type, a load with leakage, line and neutral swapped on the input, out-of-date firmware, or — less often — a genuinely failed relay inside the unit. Do not bypass it or keep resetting — the relay test exists to keep the installation safe. This is mains-side wiring and is not a homeowner job. Get the installer or a qualified engineer to check the neutral-earth arrangement, confirm line/neutral aren't swapped, and update firmware. A remote diagnostic can read the detailed step-number the GX device reports and point the engineer straight to the failing check.
VE.Bus Error 14Device cannot transmit data
The unit cannot transmit on the VE.Bus network. Victron gives the likely cause as a short circuit in the communication cables, and, very rarely, a broken component on the board. Victron's own solution is to return the device to the nearest service point for repair, so this is not a code to keep resetting. It auto-restarts once the error is gone, but a fault that returns needs the unit looked at. Note that Error 14 is not the same as Error 3, which is the code for the wrong number of devices being found on the network. Do not open the inverter/charger. VE.Bus error guide →
VE.Bus Error 17Phase master missing
In systems with more than one unit per phase, a slave unit has lost communication with the phase-master and timed out. If it appears briefly during a restart or while settings are being changed remotely, it's harmless and clears itself. Persistent causes are a cabling/communication problem on the VE.Bus network (bad RJ45 socket or cable), a blown DC fuse stopping a unit powering up when mains is absent, or out-of-date inverter/GX firmware. If it cleared on its own after a restart, no action is needed. If it persists, the network cables, GX device and units may each need checking in turn — an engineer's job, as it involves the wiring between units. Book a diagnostic; we'll review the VRM data first so a site visit (if needed) is targeted.
VE.Bus Error 25Incompatible VE.Bus configuration
The units in the system aren't a legal combination, so the system stays off until it's corrected. Victron only allows units with identical 4-digit type numbers together, and within one phase they must also share the same compatibility letter (e.g. 2623_B). It is caused by mixing inverter/charger models that aren't compatible, or running different firmware versions across the units after a partial update. Check the compatibility code on each unit's sticker (4-digit number plus a letter). Bringing all units to the same latest firmware often resolves it. Firmware and configuration changes are best done by an engineer with VEConfigure — we can do this remotely. FREE to diagnose, £125 only if we fix it.

MPPT solar charger errors (SmartSolar & BlueSolar)

These "Err" numbers come from Victron MPPT solar charge controllers (SmartSolar and BlueSolar). You'll see them in the VictronConnect app over Bluetooth, on the unit's own display where fitted, or on a GX device. Many auto-reset the moment conditions return to normal — the trick is knowing which ones point to a wiring or design problem you should act on.

Err 2Battery voltage too high
The charge controller has measured battery voltage above its safe limit and stopped charging to protect the battery. It auto-resets once the voltage falls back. Causes are another charger also connected to the same battery pushing the voltage up, the battery voltage being set lower in the app than the actual battery (e.g. a 24V pack set as 12V), or — rarely — a fault in the controller. Check in VictronConnect that the battery voltage setting matches your actual battery. If another charger or a DC-coupled source shares the battery, that interaction may be the cause. If the setting is right and it keeps recurring, book a diagnostic — we can read the settings remotely and confirm. Don't touch the DC wiring yourself.
Err 17 / Err 18Controller overheated / over-current
Err 17 means the controller is still too hot even after it cut its own output to reduce heat; Err 18 means the output current went over its safe limit. Both normally auto-reset once things cool down or the surge passes. Err 17 is driven by high ambient temperature or a blocked heatsink/poor airflow; Err 18 by a big load switching on, a sudden jump in sunlight, or an inverter overload pulling hard on the battery. Make sure the controller has clear air around it and isn't in direct sun or a sealed cupboard, and clear any dust from the heatsink. If Err 18 doesn't clear on its own, disconnect the controller from all power sources, wait 3 minutes and power up again. If overheating keeps happening in normal conditions, have it checked.
Err 33PV over-voltage
The voltage coming from the solar panels has exceeded the controller's maximum rated PV input, so it has stopped charging to protect itself. It auto-resets once the PV voltage drops about 5V below the rated maximum. The usual cause is too many panels wired in series for this controller, especially on cold, bright mornings when panel open-circuit voltage is at its highest — a string-design issue. This points to the panel array being configured beyond the controller's limit. Check the array design against the controller's max PV voltage in the datasheet — if it's borderline, the string may need re-arranging, which is an engineer's job (the DC side is live whenever it's light). MPPT error guide →
Err 38 / Err 39PV input shutdown
To protect the battery from overcharging, the controller has internally shorted its own PV input and stopped. Err 38 does not auto-reset; Err 39 resets automatically once the battery voltage drops below the maximum setting. It is caused by an incorrect battery voltage setting, or a conflict where the controller has been told (often by a BMS or a charge limit) to stop charging but the array keeps pushing power in. First, update to the latest firmware in VictronConnect. To recover Err 38: disconnect the solar panels, then the battery; wait 3 minutes; reconnect the battery first, then the panels. If it returns, the battery settings or BMS interaction need looking at — book a remote diagnostic rather than repeatedly forcing it back on. MPPT error guide →
Err 67BMS connection lost
The controller has lost its control connection to the battery's BMS. As a safety measure it drops its output right down to a low base voltage, so the battery barely charges, until communication returns. The cause is a disconnected or faulty communication cable between the charger and the BMS/GX device, or a wider comms failure on the system. Check the communication cable between the charge controller and the BMS (or GX device) is properly seated at both ends. If the controller was deliberately removed from a managed-battery system, its BMS setting may need changing back to standalone in VictronConnect — a settings job we can do remotely. Don't open the battery. FREE to diagnose, £125 only if we fix it. Battery BMS guide →
Err 116Calibration data lost
The controller can't read its factory calibration data. If it's showing as an active error now, the unit is faulty. If it only appears in the history and the charger is working normally, it can be safely ignored. It is either a hardware issue, or (harmlessly, in the log) a side-effect of firmware version changes on SmartSolar units. If it's a live, active error, the controller needs replacing — contact your dealer. If it's only in the event history and everything is charging fine, no action is needed. Unsure which? Book a diagnostic and we'll read the live status to tell you whether it's active or historical.

System, GX & VRM alarms (Cerbo GX / VRM Portal)

These aren't numbered fault codes — they're the named alarms a GX device (Cerbo GX, Color Control GX) raises and pushes to the VRM Portal, which then emails or notifies you. They summarise what the inverter, battery and BMS are reporting. They tell you something needs attention; the matching VE.Bus or MPPT code above usually tells you exactly what.

Low battery alarmBattery voltage critically low (VE.Bus)
The inverter/charger has reported that battery voltage has fallen to a critically low level. In a multi-phase system VRM and the GX device show which phase raised it. The inverter may shut down loads to protect the battery. The battery has been discharged too far — a long spell of high load with little solar or grid charging, an undersized battery for the demand, or a charge source that has failed and left standby loads draining the pack. Reduce or switch off heavy loads and let the battery recharge from solar or grid. If it keeps appearing with the battery seemingly full, the alarm thresholds or wiring may be off — a remote diagnostic can read the VRM history and settings. Repeatedly running a lithium battery flat shortens its life, so don't ignore it.
Overload alarmInverter output overloaded (VE.Bus)
The power being drawn from the inverter/charger has exceeded its rating. The GX device and VRM show which phase is overloaded. The inverter reduces output or shuts down to protect itself. The cause is too many appliances running at once, or a single high-draw load (kettle, oven, immersion heater, a motor starting) exceeding the inverter's continuous rating. Turn off some loads and let the system recover, then stagger high-power appliances rather than running them together. If the overload appears with only modest load connected, that's worth investigating — book a diagnostic and we'll review the VRM power logs. FREE to diagnose, £125 only if we fix it. Inverter overload guide →
Temperature alarmInverter/charger over-temperature (VE.Bus)
The inverter/charger is running too hot and has raised a temperature alarm, throttling output or shutting down until it cools. It is caused by high ambient temperature, the unit installed in a hot or poorly ventilated spot, blocked ventilation, or sustained heavy load. Make sure there's clear air space around the unit, it isn't boxed into a sealed cupboard or sitting in direct sun, and the vents are free of dust. Reduce load if it's been running hard. If it overheats in cool, well-ventilated conditions, the internal fan may have failed — have it checked.
High voltage alarmBattery over-voltage (battery monitor / BMS)
A battery monitor or the battery's BMS has reported pack or cell voltage above its safe limit. On managed lithium batteries this is usually the BMS flagging an internal cell imbalance near the top of charge. Causes are cells drifting out of balance as the pack approaches full, a charge source set too high, or a fault in the battery itself. Often this is a balancing issue best resolved by letting the battery complete a full, supervised charge so the BMS can re-balance the cells, plus keeping the battery firmware up to date. Do not open the battery or alter DC wiring — Victron's guidance for BMS alarms is to involve the supplier. Book a diagnostic and we'll read the cell data from VRM first.
Communication lostInstallation offline / device not communicating
VRM has stopped receiving data from the GX device, or the GX device has lost contact with one of the products in the system. You'll typically get an "installation offline" notification. Causes are loss of internet at the property, the GX device powered down or rebooting, a router problem, or a disconnected network/communication cable to one of the units. Check the GX device is powered on and the property's internet/router is working — a power-cycle of the router and GX device often restores it. If a single product (not the whole site) keeps dropping offline, the cable to that unit may be the issue: the GX device is still online, so we can confirm remotely whether it's the cable or the device, free to diagnose. If the whole site is offline, our VRM offline guide takes you through the WiFi, Ethernet and VRM checks step by step. If the GX device needs reconnecting to your WiFi, we can set it up on site, from £195: we connect it to your WiFi, set up your router, including a separate 2.4 GHz network if it needs one, and check it's reporting.
Code not listed here?

Victron's VE.Bus and MPPT error lists grow with firmware updates, and the named GX/VRM alarms summarise what the inverter and battery BMS report rather than using a fixed number. If your code isn't listed, share the exact text from VictronConnect, the GX device, or the VRM alarm log and we'll identify it. Victron's own VE.Bus and MPPT error pages and the VRM Portal manual are the authoritative references.

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Full diagnostic guides by fault type
VE.Bus error codes

VE.Bus Error 1 · 3 · 5 · 8 · 11 · 14 · 17 · 25Full diagnostic — MultiPlus & Quattro communication, blown DC fuses, the ground/relay safety self-test, and self-crimped cable faults.

See VE.Bus error codes
MPPT error codes

Err 2 · 17 · 18 · 33 · 38 · 39 · 67SmartSolar & BlueSolar — PV over-voltage string design, PV input shutdown recovery, overheating, and BMS connection loss.

See MPPT error codes
MultiPlus not charging

No charge · DVCC · charge parametersCharge parameters, BMS lockout, AC input current limit, firmware mismatch, and DVCC configuration on grid and off-grid systems.

See MultiPlus not charging
Battery BMS disconnect

High voltage · BMS lost · Err 67Third-party lithium BMS cut-outs — cell imbalance, low-temperature charge protection, SoC drift, and DVCC settings.

See battery BMS disconnect
VRM portal / Cerbo GX offline

Communication lost · Cerbo GX · WiFiInstallation-offline alarms — WiFi dropout, Ethernet DHCP, static IP, and VRM access token issues on the GX device.

See VRM portal / Cerbo GX offline
Explore

More Victron help

Victron hub

Independent Victron Energy diagnostics covering MultiPlus inverter-charger faults, VE.Bus communication errors, SmartSolar MPPT error codes, Cerbo GX.

See Victron hub
VE.Bus error codes

Your Victron system is showing a VE.Bus error — the MultiPlus or Quattro has stopped and the system is in a fault state. Free remote diagnostic.

See VE.Bus error codes
MPPT error codes

Your Victron SmartSolar or BlueSolar MPPT controller is showing an error code — most likely Error 33 (PV overvoltage) or Error 38 (PV input shutdown).

See MPPT error codes
MultiPlus not charging

Your Victron MultiPlus or MultiPlus-II runs but will not charge, and state of charge sits stuck or falling. Causes from settings to DC connections.

See MultiPlus not charging
Battery BMS disconnect

Your Victron system has stopped charging or discharging the battery — the BMS has disconnected or triggered a protection. Free remote diagnostic.

See battery BMS disconnect
VRM portal offline

Your Victron VRM portal is showing the system offline — you can't monitor battery state of charge, inverter output, or solar yield remotely.

See VRM portal offline
FAQ

Victron fault code questions

VE.Bus errors from a MultiPlus or Quattro show on the front-panel LEDs and, with a number and plain-text description, on a connected GX device (Cerbo GX or Color Control) and in the VRM Portal. MPPT errors from SmartSolar and BlueSolar charge controllers appear in the VictronConnect app over Bluetooth, on the controller's own display where fitted, or on a GX device. System-level alarms (Low battery, Overload, Temperature, High voltage, Communication lost) are raised by the GX device and pushed to VRM, which can email or notify you. For a full history, open VRM and check the alarm log.
Many do. VE.Bus Error 1 (a phase switched off) and Error 17 (phase master missing) recover automatically once the underlying alarm clears or after a restart. On the MPPT side, Err 2 (battery voltage too high), Err 17/18 (overheat/over-current), Err 33 (PV over-voltage) and Err 39 (PV input shutdown) all auto-reset once conditions return to normal. Err 38, however, does not auto-reset — you recover it by disconnecting the PV then the battery, waiting 3 minutes, and reconnecting the battery first then the panels. If a code keeps coming back after it self-clears, the underlying cause needs diagnosis.
Error 8 (ground relay test failed) and Error 11 (relay test fault) mean the inverter/charger ran its automatic safety self-test on the internal earth and back-feed relays and it failed, so the unit will not connect to the grid. On MultiPlus-II and EasySolar-II it is most often an installation or wiring problem — incorrect neutral-to-earth wiring for your installation type, a load with leakage, line and neutral swapped on the input, or out-of-date firmware — rather than a broken unit, but it is a protective shutdown that must not be bypassed or repeatedly reset. This is mains-side wiring and is not a homeowner job; get a qualified engineer to check the neutral-earth arrangement and update firmware. See our full VE.Bus error guide.
Err 33 (PV over-voltage) means the voltage from the solar panels has exceeded the controller's maximum rated PV input, so it has stopped charging to protect itself — usually too many panels wired in series for that controller, most likely to trigger on cold, bright mornings when panel open-circuit voltage is highest. It auto-resets once PV voltage drops about 5V below the rated maximum. Err 38 (PV input shutdown) means the controller has internally shorted its own PV input to stop the battery overcharging, typically from an incorrect battery voltage setting or a BMS/charge-limit conflict. Err 38 does not auto-reset: disconnect the panels then the battery, wait 3 minutes, reconnect the battery first then the panels, and update firmware in VictronConnect. See our full MPPT error guide.
The remote diagnostic is free — our engineers review your VRM data, alarm history and settings without visiting site. If we can fix it remotely — a VEConfigure or VictronConnect settings change, a firmware update, or a BMS/standalone setting — it is £125, and you only pay if we actually fix it. If it needs hands-on work, such as DC-side or VE.Bus wiring, we tell you that first. Either way you avoid an unnecessary callout.
Usually the same day. Most Victron faults are confirmed in a single 30-minute remote session — we read your VRM alarm history and live data while you describe what the system is doing. You get a written summary of the cause and the recommended fix straight after the call.
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